Hello everyone. The eyelet that the hook on the heat sink hooks to
broke off from the motherboard so the heatsink isn't touching the
chipset (not the cpu). So now the computer won't boot and I'm afraid
my notherboard is toast but I don't see any visible signs of damage.
Nothing melted or black or anything. Is there a way I can tell for
sure?
Before you panic, there are some particular motherboards, where
there is an electrical "continuity check" *through* the wire that
holds the Northbridge heatsink in place. If the eyelet pops out,
not only does your Northbridge lack a proper cooling solution,
but the PC will not operate.
You have to re-establish electrical contact, in order to make the
computer work again. A neat safety feature, but it never would have
been necessary if a decent mechanical solution had been used in
the first place. Imagine, for example, a solution using nuts and
bolts and tensioning springs. That would never have failed, and
would never need a continuity check. The fact a continuity check
exists, tells me the motherboard engineer *knows* the eyelets fall out!
In this picture, a tiny bit of electricity, flows from one hook
eye, to the other hook eye, through the steel wire. The continuity
circuit checks that the current is flowing. You have to restore
that electrical path, for the motherboard to be working.
http://www.the-nextlevel.com/tnl/attachment.php?attachmentid=19074&stc=1
Now, I have a motherboard with those eyelets, and the problem with them,
is they're made of the wrong metal. They look like they're stainless,
and stainless doesn't solder worth a damn. They should be made from
copper wire with a tin-lead finish, so that solder would wet them.
If you have calipers, you can measure the eyelet wire diameter, then
shop for a common leaded resistor at Radio Shack. A 1/2 watt or 1 watt
resistor, may have legs made of "good metal". You buy the resistor, snip
off a leg, bend it into a U, and insert it where the eyelet used to be.
The holes in the motherboard, must be cleared of solder first, using
either a soldering iron and "solder wick" or a vacuum solder sucker
(manual device, plunger operated). Once the hole is clear of solder,
the makeshift eyelet will pass through the hole. "Swage" the ends
of the "U" a little bit, to take the mechanical tension off the solder
joint.
___
/ \
| |
---+ +--- <---- Bend a little bit of leg, on the backside of the
motherboard, so the makeshift eyelet won't fall
out. With the motherboard inverted, solder side
pointing upwards, gravity will keep it in place.
The bent portion of leg, should not extend past the
solder pad. As drawn, this diagram has too much leg
in the bent position. You only want a little bit of
bent portion, to prevent the thing from pulling out.
Once you're finished soldering, then hook the spring steel wire into place.
Also make sure the heatsink has some thermal interface material (thermal paste
or a replacement thermal pad) to complete the installation. Thermal paste,
helps the heat flow from the Northbridge, into the heatsink. An air gap,
by comparison, is a "heat insulator".
When the steel wire is back in place, you should have electrical continuity,
and the motherboard should start again, once you restore all the rest of
the connectors and wiring.
If you've never done this kind of repair before, or taken a computer
apart, take the computer to a TV repair shop and they'll know what to do.
Explain that the eyelet needs to be replaced with something that can
be soldered, and they'll know exactly how to do it. Tell them not
to forget the thermal paste when they pop the heatsink back on.
A little Ceramique or AS5 would do, being careful not to get it
all over the place.
HTH,
Paul
